Add a typescript test (not just a compile test) for enums

[thomasetter]

Also changed from opt-in to opt-out for running TypeScript tests.

This will make sure that new tests are run by default.

[thomasetter]

Friendly ping :)

[daxpedda]

LGTM!

@Liamolucko would you mind taking a look at this? Unfortunately I'm completely unfamiliar with TS, so I don't feel comfortable approving something like this.

[Liamolucko]

Personally I don't think this is super necessary, I think a compile test is enough: making sure that wasm-bindgen works properly at runtime is already covered by the regular tests in tests/wasm.

Having extra tests doesn't hurt though, so I'm fine to merge this regardless.

[thomasetter]

Thanks, just for the motivation why I am doing this:
The problem with compile-only tests is that they just assert properties of the binding (.d.ts), however the binding and the underlying JS can (and I believe in the past have, but do not remember the location/commits) drift apart, which will then only be discovered by users after a release.

[Liamolucko]

Thanks!